/**
 * CURL SSRF Example
 *
 * @author Feei <wufeifei@wufeifei.com>
 * @link   http://wufeifei.com/ssrf
 */
function callback($callback_url){  
    /*
     * 此处$callback_url取函数入参
     * 扫到这类规则后
     * 需要将callback()函数作为__搜索(S)__规则添加一个新的扫描规则
     */
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $callback_url);
    curl_setopt($ch, CURLOPT_HEADER, 0);
    curl_exec($ch);
    curl_close($ch);
}